Sisters can be each other's best friends or worst enemies, depending on the day. However, as these quotes about sisters for National Sibling Day help demonstrate, no matter how much two sisters may argue, they are always better together. No one gets you quite like a sister will, and for that reason, there's almost nothing that two sisters can't conquer when they put their minds to it.

If you're an older sister, you wouldn't let a soul hurt your little sister, and if you're a little sister, your older sister is pretty much the coolest person to ever live. OK, so maybe all sister relationships don't exactly function that way, but there is an undeniable bond between every set of sisters. No matter how competitive you and your sis may be, there's no denying the fact that she'll be your support system if you need her to be. As one of these thoughtful quotes points out, the sister relationship is often the most complex, but it is also the strongest of all relationships.

Take some time to read through these sister inspired quotes this National Sibling Day and share your favorite with your sister. Whether it be through a text, a card, or a Facebook wall posting, there's plenty of love to go around, so don't be the one to stop its flow.

1. "Sister is probably the most competitive relationship within the family, but once the sisters are grown, it becomes the strongest relationship." — Margaret Mead

2. “Sisters function as safety nets in a chaotic world simply by being there for each other.” — Carol Saline

3. "Lord help the mister that comes between me and my sister..." — Irving Berlin